Screen is a full-screen window manager that multiplexes a physical terminal between several processes, typically interactive shells. Each virtual terminal provides the functions of the DEC VT100 terminal and, in addition, several control functions from the ANSI X3.64 (ISO 6429) and ISO 2022 standards (e.g., insert/delete line and support for multiple character sets).

The xterm program is the standard terminal emulator for the X Window System. It provides DEC VT102/VT220 and Tektronix 4014 compatible terminals for programs that can't use the window system directly. If the underlying operating system supports terminal resizing capabilities (for example, the SIGWINCH signal in systems derived from 4.3bsd), xterm will use the facilities to notify programs running in the window whenever it is resized.

rxvt-unicode is a clone of the well known terminal
emulator rxvt, modified to store text in Unicode
and to use locale-correct input and output. It
also supports mixing multiple fonts at the same
time, including Xft fonts, real transparency, and
an optional embedded Perl interpreter that allows
you to extend your terminal easily.

x11vnc allows one to remotely view and interact with real X displays (i.e. a display corresponding to a physical monitor, keyboard, and mouse) with any VNC viewer. It is designed to be compatible with all Unix variants and Mac OS X, and depends on a small set of standard libraries. It supports SSL/TLS and VeNCrypt encryption, Unix password logins, single port access, Zeroconf, file transfer, and UltraVNC extensions. It is part of the LibVNCServer project.

aterm (AfterStep term) is an xterm replacement, based on rxvt v.2.4.8. It includes features such as NeXT style scrollbar, resource efficient pseudo-transparency. It understands root background changes by AfterStep Pager and Esetroot. The primary goal of aterm is to provide cool visual features without resource consumption. It can be compiled to utilize AfterStep's libasimage for wider image format support.

Anyterm provides a terminal emulator on a Web page using Javascript and a server daemon. The daemon typically runs behind an HTTP proxy; it forks a shell and communicates with the script using XMLHTTP on port 80 or securely using SSL. This provides you with shell access to your machine from almost any Web browser, even when firewalls are in the way. The my.anyterm.org service provides access without the need to install anything on your servers.

Thinstation is a mini Linux distribution that
enables you to convert standard PCs into
full-featured, diskless thin clients supporting
all major connectivity protocols like Windows
terminal services (RDP), Citrix Ica, X, NX,
telnet, ssh, etc. It can be booted from the
network using Etherboot/PXE or from standard media
like floppy/CD/hd/flash-disk etc. The
configuration is centralized to simplify terminal
management.

Rxvt is an 8-bit clean, colour xterm replacement that uses significantly less memory than a conventional xterm, mostly since it doesn't support toolkit configurability or Tek graphics, but also since features can be removed at compile-time to reflect your needs.

Eterm is a vt102 terminal emulator intended as a replacement for xterm. It is designed with a Freedom of Choice philosophy, leaving as much power, flexibility, and freedom as possible in the hands of the user. It is designed to look good and work well, but takes a feature-rich approach rather than one of minimalism. Current features include color support, background images (all Imlib-supported formats), theme support, and pseudo-transparency.